Hello, On 11/19/2010 04:45 PM, Alan Stern wrote: > This patch (as1431b) makes the synchronous runtime-PM interface > suitable for use in interrupt handlers. Subsystems can call the new > pm_runtime_irq_safe() function to tell the PM core that a device's > runtime-PM callbacks should be invoked with interrupts disabled > (runtime_suspend and runtime_resume callbacks will be invoked with the > spinlock held as well). This permits the pm_runtime_get_sync() and > pm_runtime_put_sync() routines to be called from within interrupt > handlers. > > When a device is declared irq-safe in this way, the PM core increments > the parent's usage count, so the parent will never be runtime > suspended. This prevents difficult situations in which an irq-safe > device can't resume because it is forced to wait for its non-irq-safe > parent. > > Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > > --- ... > > + void pm_runtime_irq_safe(struct device *dev); > + - set the power.irq_safe flag for the device, causing the runtime-PM > + callbacks to be invoked with interrupts disabled > + > void pm_runtime_mark_last_busy(struct device *dev); > - set the power.last_busy field to the current time > > @@ -438,6 +454,16 @@ pm_runtime_suspended() > pm_runtime_mark_last_busy() > pm_runtime_autosuspend_expiration() > > +If pm_runtime_irq_safe() has been called for a device then the following helper > +functions may also be called in interrupt context: I was wondering what is the proper usage of this API. From a point of view of a driver, does it mean that in runtime_resume/runtime_suspend helpers any blocking calls cannot be used, so the device driver is prepared for situations when some other subsystem invokes pm_runtime_irq_safe() on its device? Or is pm_runtime_irq_safe() intended to be called only by the device driver in such case? I'd like to use blocking calls for a voltage regulator control within the runtime PM helpers in the driver but I'm not sure whether this wouldn't violate the API. Thanks, Sylwester > + > +pm_runtime_idle() > +pm_runtime_suspend() > +pm_runtime_autosuspend() > +pm_runtime_resume() > +pm_runtime_get_sync() > +pm_runtime_put_sync() > + > 5. Run-time PM Initialization, Device Probing and Removal > > Initially, the run-time PM is disabled for all devices, which means that the > -- Sylwester Nawrocki Samsung Poland R&D Center _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
